JP2510258Y2 - Material testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a material testing machine capable of efficiently and safely applying a test load.

[Prior Art] There is a universal material testing machine in which a crosshead is attached to a screw rod erected on a bed so that the crosshead can be raised and lowered, and a table is independently raised and lowered by a hydraulic device provided on the bed.

When performing a compression test with this type of tester, for example, a compressive load is applied to the test piece between the upper platen provided on the crosshead and the lower platen provided on the table, but before the actual test load is applied. In addition, it is necessary to lower the crosshead toward the test piece, and immediately before the upper platen comes into contact with the test body, the lowering of the crosshead is temporarily stopped and brought into contact slowly. For this adjustment operation, (1) 0N-OFF the drive while observing the movement of the crosshead, or (2) install a limit switch at a position according to the height of the test body between the table and the crosshead. Use the limit switch to stop the descent, or (3) provide a gap between the upper platen and the crosshead so that the platen comes into contact with the specimen to activate the limit switch and stop the descent. Has been done.

[Problems to be Solved by the Invention] The conventional adjustment operation method described above has the following problems. In the case of (1), the operator visually performs a stop operation, which may cause the test piece to stop earlier than the position immediately before contact or collide with the test piece, resulting in poor operability and destruction of the test piece or test. It was a cause of machine failure. In the case of (2), the position where the limit switch is set must be adjusted according to the heights of various test bodies having different heights, and the work is complicated and the operability is poor.
In the case of (3), it is difficult to perform zero adjustment of the load accurately, and the platen is not well fitted because it is installed with a gap.

Therefore, an object of the present invention is to provide a material testing machine which can perform the adjustment with good operability and which does not cause the destruction of the test body or the failure of the testing machine.

[Means for Solving Problems] The present invention adopts the following configuration in order to solve the above problems.

That is, a material testing machine according to the present invention is provided with a table and a crosshead, and a test piece held between the crosshead and the table is loaded with a test load. A photoelectric sensor for detecting the tested test piece is provided on the crosshead side, and based on the detection result of the photoelectric sensor, the driving speed of the crosshead or the table immediately before the crosshead-side load member contacts the test piece. It is characterized in that drive control means for reducing or stopping is provided.

[Operation] When the crosshead or the table is moved to adjust the test space between the two, if the end of the test piece provided on the table side interrupts the optical path of the photoelectric sensor provided on the crosshead side, The sensor detects the test piece, and the driving of the crosshead or the table is stopped immediately before the test piece contacts a member on the crosshead side such as the upper platen.

[Embodiment] FIG. 1 is a view showing an embodiment of the present invention.
The crosshead 6 is attached to the screw rods 3 and 3'standing on the bed 2 via nuts 5 and 5 '. A cylinder 7 is fixed to the bed 2, and a table 10 is attached to a ram 8 fitted in the cylinder 7.

An elevating motor 12 is attached to the crosshead 6, and a worm (not shown) provided on a rotation shaft of the motor rotates the worm wheel by differentially rotating the motor, and screw rods 3, 3'that are screwed to the worm wheel are screwed. The crosshead 6 moves up and down along. The displacement of the cross head 6 is detected from the rotation speed of the rotation shaft of the motor detected by the pulse encoder 13 and the pitch of the screw rod. On the other hand, the table 10 also rises due to the rise of the ram 8, and this displacement is detected by the displacement detector 14 of the differential transformer type.

An upper platen 16 as a crosshead-side load member is provided on the central lower surface of the crosshead 6, and a lower platen 17 as a table-side load member is provided on the central upper surface of the table 10. A test load is applied to the test piece 18 installed on the lower platen 17 by the platen.
This load is detected by the load cell 19 provided on the upper platen 16.

As shown in FIG. 2, photoelectric sensors 21, 22 and 2 are provided at positions where the left and right end portions of the lower surface of the crosshead 6 sandwich the screw rods 3, 3 '.
A set of 3, 24 (21, 23 is a light emitting element, and a set of 22, 24 is a light receiving element) is provided under the upper platen 16 so that the light projecting paths intersect each other. The photoelectric sensors 21, 22 and 23, 24 are operated when the crosshead 6 descends and the projecting path is blocked by the test piece 18 immediately before the upper platen 16 contacts the test piece 18. By the operation of the photoelectric sensor, the approach of the test piece 18 to the upper platen 16 is detected, and the detection signal is output to the tester control device (drive control means) 25. The tester control device 25 is a device that controls the movement of each part such as a table and performs data processing by inputting a displacement detection signal and a load detection signal. Immediately after the detection signal from the photoelectric sensor is input, the crosshead 6 Stop moving.

Thus, in the apparatus of the above-described embodiment, when the crosshead 6 is moved to adjust the test space according to the height of the test piece, the test is performed immediately before the upper platen 16 provided on the crosshead 6 contacts the test piece 18. The strip 18 blocks the optical path of the photoelectric sensor, and at this time, the controller 25 issues a command to stop the lowering of the crosshead 6, so that the upper platen does not collide with the test piece and the test piece is destroyed or the tester There is no situation that damages the. Such a stopping operation is performed even immediately before the upper platen comes into contact with the test piece evenly for various test pieces having different heights. Therefore, a limit switch is installed for each test piece as in the conventional case. No work is required, and the test space adjustment operation can be performed efficiently. Also,
If the output of the crosshead descent stop signal can be freely set by a delay circuit such as a timer, the photoelectric sensor detects the approach of the test piece by setting the delay time appropriately, and the rear upper platen It is possible to adjust the descending stop position of the crosshead until just before the contact with the test piece, and to perform zero adjustment of the load before starting the test. Further, even if the operator mistakenly puts his / her hand between the test piece and the upper platen, the descending of the crosshead is stopped, so that the test can be safely performed.

In the above embodiment, the photoelectric sensor is used as a transmission type, but a reflection type or the like can be used. Also,
When performing a bending bending test, the contact position between the fulcrum (punch) and the test piece can be set, and when performing the tensile test, the gripping teeth on the crosshead and the grip position of the test piece can also be set. it can. The number of photoelectric sensors may be one, but in the case of two photoelectric sensors as shown in the figure, the heights of the photoelectric sensors may be changed to a two-step detection method so that the speed is controlled in two steps.

[Effects of the Invention] As is apparent from the above description, the material testing machine according to the present invention enables the test space to be adjusted efficiently regardless of the type of the test piece, resulting in the destruction of the test piece and the testing machine. It is now possible to safely apply the test load without causing a failure or the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention, and FIG. 2 is a diagram showing a configuration of essential parts. 6 …… Crosshead, 10 …… Table 16 …… Upper platen, 17 …… Lower platen 18 …… Sample piece 21,22,23,24 …… Photoelectric sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-167436 (JP, A) JP 61-250512 (JP, A) Actual opening 59-100096 (JP, U) Actual opening 58- 182142 (JP, U) Actually open 60-95543 (JP, U) Actual public 52-17349 (JP, Y2) Actual public 61-16508 (JP, Y2) Actual public 61-20512 (JP, Y2)

Claims (1)

(57) [Scope of utility model registration request] 1. A material testing machine, comprising a table and a crosshead, wherein a test load is applied to the test piece held between the crosshead and the table, and the test piece provided on the table-side load member is detected. A photoelectric sensor is provided on the crosshead side, and based on the detection result of the photoelectric sensor, the driving speed of the crosshead or the table is reduced or stopped immediately before the crosshead-side load member contacts the test piece. A material testing machine comprising drive control means for controlling the material.